Simultaneous efficient adsorption and accelerated photocatalytic degradation of chlortetracycline hydrochloride over novel Fe-based MOGs under visible light irradiation assisted by hydrogen peroxide

Abstract

In light of recent events, it is becoming extremely difficult to ignore the serious environmental pollution caused by pharmaceuticals in water. In this study, two novel metal–organic gels (MOGs), JLUE-MOG-1 and JLUE-MOG-2, were successfully synthesized using a solvothermal method and then used for photocatalytic removal of a typical pharmaceutical [chlortetracycline hydrochloride (CTC)] from water. After treatment with a freeze-drying procedure, the resultant metal–organic aerogels were obtained and their morphologies and porous structures were fully characterized using SEM, TEM, TGA, PXRD, UV-Vis, FT-IR, XPS and nitrogen adsorption measurements. The accessibility of the porousness was verified from the adsorption performance, which was investigated to keep to the pseudo-second-order kinetic model and the Langmuir isotherm model. Furthermore, the catalytic tests disclosed that JLUE-MOG-1 showed an extremely high photocatalytic activity, which largely outperformed JLUE-MOG-2 in terms of larger specific surface area and better response to visible irradiation caused by the Fe–O clusters. Furthermore, because of the synergistic effect of the Fenton-like reaction and photocatalytic process, the photocatalytic performance of JLUE-MOG-1 could be enhanced in the presence of hydrogen peroxide (H₂O₂). Then, the effects of photocatalyst dosage, H₂O₂ concentration and initial solution pH on the photocatalytic degradation of CTC were examined. Therefore, because of a combination of high porosity, hierarchical pore structures, easily accessible triazine-moieties and Fe-functionalities, an efficient and recyclable heterogeneous photocatalyst, with a high throughput and a wide operating range, for wastewater treatment was successfully achieved.